ecurelix,
I appreciate your valuable comments. However, unfortunately the 345 and 77L are two totally different animals.
SQ is using it on shorter legs in order to get a higher utilization. Each and every airline that had 345s are replacing them with 77Ls, except for SQ. EK had wanted to get rid of them for sometime, in favor of replacing them with 77Ls.
The 77L burns 0.032 L per seat/km as opposed to 345's 0.038 L.
PIA flies them on longer-hauls largely because they cannot make money on ULHs.
The 777 clearly has a direct advantage, in maintenance as well. Given it is far more reliable than the competing 345s. The GE90, even with ETOPS, is one of the most reliable. And keep in mind, the quad vs twin doesn't make costs much different. 772ERs available are old - I agree. However I believe they will still have a higher resale value than the fast-decreasing in value 345s.
As per the engine delivering, well you know, you rarely need to change one in service.